Why won't the material node displacement work in cycles
Change the displacement type found in the Properties window under Object Data from (the default) Bump to True.
Note that this is an experimental feature and you must change the feature set from Supported to Experimental in Properties &gt; Render Settings &gt; Render.

True Displacement: Mesh vertices will be displaced before rendering, modifying the actual mesh. This gives the best quality results, if the mesh is finely subdivided. As a result this method is also the most memory intensive.
Bump Mapping: When executing the surface shader, a modified surface normal is used instead of the true normal. This is a quick alternative to true displacement, but only an approximation. Surface silhouettes will not be accurate and there will be no self shadowing of the displacement.